Combination tools have been known for some time. One plier type combination tool is described in U.S. Pat. No. 1,321,777 which issued in 1919. That tool combined a plier screwdriver and adjustable wrench. Other such tools are shown in U.S. Pat. Nos. 1,739,658, 1,802,666, 2,271,680 and the recently issued U.S. Pat. No. 3,760,473.
Although combination tools of the plier type ahve been known for many years and have the advantages of convenience and lighter weight over separate tools to do the same jobs, they have generally achieved these advantages at the cost of efficiency for one or more of the specific tasks for which they are adopted. That is, in attempting to be jacks of all trades, they are rarely able to master even one. For example, the tools shown in U.S. Pat. Nos. 1,321,777 and 1,739,658 feature a screwdriver blade at the end of one of the handles of a plier. Now, as anyone who has used such a tool as shown in U.S. Pat. No. 1,739,658 as a screwdriver will attest, this arrangement is far from satisfactory. The main drawback is the requirement that the user grip the sharp jaws of the plier when applying pressure down on the screw to be driven. The U.S. Pat. No. 1,321,777 tool overcomes this disadvantage to some extent but only at the cost of added provisions and inconvenient extra operations in setting up the tool for use.
Further, when trying to extract a stubborn screw with non-combination tools, it is often convenient to use pliers or a wrench to grip the screwdriver shaft to apply more torque to the screw than is easily done through the screwdriver handle alone. If one has only a combination plier tool, this dual use of plier and screwdriver can either not be done or not be done well.